Does Copper Dissolution Impact Through-Hole Solder Joint Reliability?
Bibliographic record
Abstract
ABSTRACT The process issues relating to high copper dissolution rates have been well documented within the industry. The copper dissolution rates of SAC305/405 plus many of the leading alternative lead-free wave alloys have been characterized and pin-through-hole rework process windows assessed. One remaining gap within the industry is the understanding of how copper dissolution or thinning of the through-hole barrel wall/knee locations impacts the thermal and mechanical reliability of a pin-through-hole joint. This paper provides a summary of previous work performed to study and characterize the copper dissolution rates of various Pb-free wave alloys, as well as attempts to assess the impact of high levels of copper dissolution on the thermal reliability of a 14 I/O PDIP connector. A total of five PDIP connectors were designed onto a test vehicle, each individually daisy chained using bottomside traces, for in-situ monitoring. A design of experiment was defined as an attempt to vary the level of plated copper remaining after simulating the rework of the five PDIP connectors. Each board was subjected to 0-100°C ATC for 6,000 cycles with in-situ monitoring to detect failures throughout testing using data loggers. The results from this work indicate reliability concerns when a severe degree of copper dissolution occurs and shows signs of reduced reliability due to thinning of the copper plating thickness at the knee location. In addition, mechanical and thermo-mechanical loading are key elements necessary to confirm the reliability of a pinthrough-hole joint, this paper however, focuses on thermal fatigue reliability assessment. Lastly, this paper will highlight limitations of the copper plating measurement methodology used and suggests alternative non-destructive options to inspect for copper dissolution within manufacturing environments.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".